1. Field of the Invention
The present invention relates to a device for controlling dynamic convergence by using a digital controlling method to correct arbitrary convergence astigmatism of a screen in a reflection yoke of a CRT picture device, and in particular, to a method for controlling digital dynamic convergence and a system thereof to perform individual and independent correction of the convergence with respect to each crossing point of a cross hatch pattern on a screen by receiving correction data from outside and storing the same in memory, reading the correction data from the memory, and converting the correction data to a voltage or a current so as to have a structure of outputting to magnetic field adjusting coils.
The present invention also relates to a method for controlling digital dynamic convergence and a system thereof for correcting convergence that enables a worker to perform approximate correction by generating correction data according to linear interpolation with respect to areas between crossing points when correcting each of the crossing points on a screen of a cross hatch pattern.
2. Description of the Prior Art
In general, the deflection yoke (DY) performs a function of deflecting R, G, B electron beams to desired positions on a screen of a CRT picture device. As the screens tend to be highly defined, it is impossible to achieve the converging function of the screen with the deflection yoke alone. Therefore, diverse kinds of correcting devices are usually mounted on the deflection yoke.
Of the diverse kinds of correcting devices, a dynamic convergence controller is widely used for actively controlling the converged state of the screen by attaching magnetic field adjusting coils having a structure of two poles, four poles or six poles operated under a principle of a convergence purity magnet (CPM), and moving the relative positions of R, B beams with respect to the G beam.
In particular, it is critical to apply the dynamic convergence controller to a highly defined screen leveled to a HD TV for transferring character information and graphic processing, etc. to conform to an appearance of digital TV broadcasting.
A circuit in the conventional dynamic convergence controller for a deflection yoke comprises a plurality of resistors, inductors, condensers and diodes, etc. The circuit is operated in the manner of correcting astigmatism of the screen by manually handling the controlling means such as variable resistors, etc. so as to control intensity of the current flowing in the magnetic field adjusting coils.
A current waveform predetermined in the magnetic field adjusting coils can only be applied with the adjusting circuit of the above type. Thus, the conventional adjusting circuit has a technical limit of correcting convergence astigmatism of only a few limited patterns. Furthermore, correcting a misconvergence of one area of the screen results in subsequent variation of a misconvergence of another area. Therefore, it is quite difficult to correct all the misconvergence of the entire screen.
Moreover, a worker checks the degree of convergence astigmatism with naked eyes, and properly adjusts the controlling means based on his/her own experience to correct the convergence astigmatism. Hence, it is almost impossible to correct the misconvergence of a CRT picture device having a large and flat screen with a superluminal angle to a desired level by means of such a conventional method.
The devices suggested to overcome the limit of the conventional method of measuring the convergence astigmatism with naked eyes as described above are display characteristics measuring units for measuring display characteristics of a convergence in a display device such as a color TV, color liquid crystal display (LCD) or a color plasma display panel (PDP).
This kind of a display characteristics measuring unit includes a photographing unit for separating a particular measured pattern containing a display of colors into each color component of R, G, B on a display device to be measured and photographing the same, an image processing unit for processing images of each color component and performing a predetermined further processing, and a display unit for displaying the measured result.
For instance, as disclosed in Japanese Laid-Open Patent Gazette No. 1996-307898, the convergence measuring unit photographs a white measured pattern displayed on a color CRT to be measured by a camera having a color area sensor such as a CCD, calculates a luminous center for each color component of the photographed images R, G, B while the image is processed, and displays a relative displacement of the luminous center in the amount of misconvergence.
Accordingly, the misconvergence measuring unit calculates an emitting position of a measurement pattern of each color component on a display surface of the color CRT that is measured by an image-fixed position of the measurement pattern of each color component on a photographing surface of a color camera, as well as a relative variation of the emitting position of each color component.
However, this technology poses a problem that a degree of precision easily varies depending on the temperature and humidity. For this reason, this technology is corrected by using a particular correction chart before measurement as shown in the accompanying FIG. 1.
According to the correcting method shown in FIG. 1, a correction chart 103 illuminated by a fluorescent lamp 104 (a chart including a cross hatching pattern 105 on a plate of an opaque white color) is photographed by a photographing device 101 of a convergence measuring unit 100, and the correction data showing relative positional relations between each area sensor is calculated by using the photographed image. The calculated correction data is stored in a memory within a main body 102 of the device so as to be used as data for correcting variation of the luminous center position of the measurement pattern of each color component.
According to the conventional method for correcting the relative variation of an area sensor, a position (an absolute position) of each area sensor in a reference coordinate of a convergence measuring system is calculated by using image data of each color component obtained by photographing a particular correction chart, while a relative variation of the area sensor is calculated based on that calculation. Because of the numerous computing parameters (mediating variants), a long period of time is consumed for computation.
Moreover, since a particular correction chart is used rather than a measurement pattern displayed on the CRT to be measured, a problem has arisen that it is inconvenient and difficult to correct a convergence measurement system in a production line.
The recently developed technology to overcome the above problem is the technology disclosed in Korean Laid-Open Patent Gazette No. 1999-013780. The disclosed technology is related to an automatic convergence measurement device for a color CRT.
The accompanying FIG. 1 is a schematic view illustrating construction of a convergence-measuring unit 1 for a color CRT. The convergence-measuring unit 1 comprises a photographing unit 2 and a measuring unit 3.
The photographing unit 2 photographs a predetermined measurement pattern (for instance, a cross hatching pattern, a dot pattern, etc.) displayed on a display surface of the color display 4 to be measured. A pair of photographing cameras 21, 22 is installed at the photographing device 2 for sensing images by using a stereovision method.
The measuring unit 3 computes an amount of misconvergence of a color display by using image data of the measurement pattern obtained by the photographing device 2, and displays the computed result on a displaying unit 36.
The photographing camera 21 is a color photographic device of a three-plate type, comprising a dichroic prism 212 installed at inside of the photographing unit 2 for separating the light into three colors at a rear side of the photographing lens 211, and photographing elements 213R, 213G, 213B of a solid state including the CCD area sensor allocated at the position opposed to the injecting surface of the dichroic prism 212, in which the layers of each color R, G, B appear. The photographing camera 22 is also a three-plate type color-photographing device similar to the photographing camera 21.
Installed at the photographing device 21 are a photograph controlling unit 214 for controlling operation of the photographing elements (hereinafter, referred to be as xe2x80x9cCCDxe2x80x9d) 213R, 213G, 213B of a solid state, a focus control circuit 215 for automatically adjusting the focus by operating the photographing lens 211, and a signal processing circuit 216 for processing a predetermined image transmitted from the CCD 213R, 213G, 213B and for outputting the processed image to the measuring unit 3. Likewise, the photograph controlling unit 224, the focus control circuit 225, and the signal processing circuit 226 are installed at the photographing camera 22.
The photograph controlling unit 214 is controlled by a photograph control signal transmitted from the measuring unit 3, and the photographing operation (charge accumulating operation) of CCD 213R, 213G, 213B is controlled by the photograph control signals. Likewise, the photograph controlling unit 224 is also controlled by a photograph control signal transmitted from the measuring unit 3, and the photographing operation of CCD 213R, 213G, 213B is controlled by the photograph control signals.
The focus control circuit 215 is controlled by a focus control signal transmitted from the measuring unit 3. A front group 221A of the photographing lens 221 is operated by the focus control signal so as to fix optical image of the measurement pattern displayed on the displaying surface of the color display 4 on the photographing surface of the CCD 213R, 213G, 213B.
Likewise, the focus control circuit 225 is controlled by the focus control signal transmitted from the measuring unit 3. A front group 221A of the photographing lens 221 is operated by the focus control signal so as to fix optical image of the measurement pattern displayed on the displaying surface of the color display 4 on the photographing surface of the CCD 213R, 213G, 213B.
The focus control is performed by a signal from the control unit 33, e.g., by an equal calculation method. To be specific, in case of the photographing camera 21, the control unit 33 extracts a green high frequency component (an end portion of the measurement pattern) photographed by the CCD 213G, and outputs such a focus control signal to the focus control circuit 215 so that the high frequency component may become maximized.
The focus control circuit 215 moves the front group 211A forward and backward to finally set the photographing lens 211 at a focused position by focusing the front group 211A and slowly shortening the moving distance according to the focus control signal.
The focus control is performed by using an image photographed according to the embodiment of the present invention. However, a distance sensor is installed at the photographing cameras 21, 22, and the photographing lens 211, 221 can be operated by using distance data between the photographing cameras 21, 22 detected by the distance sensor and the display surface of the color display 4.
The measuring unit 3 comprises an analog/digital (A/D) converter 31A, 31B, an image memories 32A, 32B, the control nit 33, a data input unit 34, a data output unit 35, and the display unit 36.
The A/D converters 31A, 31B convert the image signal (analog signal) inputted from the photographing cameras 21, 22 to image data of a digital signal format. The image memories 32A, 32B store the image data outputted from each of the A/D converters 31A, 31B.
Three A/D converting circuits corresponding to the image signals R, G, B of each color component are installed at each of the A/D converters 31A, 31B. Each of the image memories 32A, 32B includes three frame memories corresponding each color component R, G, B.
The control unit 33 is an operation control circuit including a microcomputer in which a memory 332 including a ROM and a memory 331 including a RAM are installed.
A program performing a convergence measurement (a series of operations including an operation, photographing, computation of image data in an optical system) as well as data (correction values, data converting tables, etc.) required for computation are stored in the memory 331. The memory 332 provides a data area and a working area for performing diverse operations to perform the convergence measurement.
The amount of misconvergence computed by the control unit 33 (measured result) is stored in the memory 332, outputted to the displaying unit 36, and displayed in a predetermined display format. The amount of misconvergence is also outputted to an external device connected thereto (a printer or an external storing device) through the data output unit 35.
The data input unit 34 inputs diverse data for convergence measurement, and includes a keyboard, for instance. The data input unit 34 also inputs data such as a measuring point on the displaying surface of the pixel-arranging pitch color display 4 of the CCD 213, 223 through the data input unit 34.
The color display 4 to be measured includes an operation control circuit 42 for controlling the color CRT 4 displaying video images and operation of the color CRT. The video signals of the measurement pattern generated by a pattern generator 5 are inputted to the operation control circuit 42 of the color display 4 to operate the deflection circuit of the color CRT 41 in turn, and to display a cross hatching measurement pattern as displayed in FIG. 3, for example.
The measurement pattern images displayed on the color display 4 are photographed as a stereovision by the photographing cameras 21, 22 of the photographing unit 2. An amount of misconvergence is measured by image data obtained by the photographing cameras 21, 22.
To be specific, the accompany FIG. 3 is a diagram displaying the cross hatching pattern 6 displayed on the color CRT 41. The cross hatching pattern 6 is generated by crossing of a plurality of vertical lines with a plurality of horizontal lines, and displayed at a suitable size to include a plurality crossing points within the displaying surface 41a of the color CRT 41. The misconvergence amount measuring areas Al to An are set on an arbitrary position so as to have a single crossing point.
In each measuring area A(r) (r=1, 2, . . . n), the misconvergence amount xcex94DX in the horizontal direction (X direction in the XY coordinate system) is computed by a photographed image of a vertical line included in the measuring area A(r), while the misconvergence amount xcex94DY in the vertical direction (Y direction in the XY coordinate system) is computed by a photographed image of a horizontal line.
Even if accurate data are secured by the conventional art described with respect to the misconvergence, the ultimate object to be controlled for adjustment of the convergence is limited to the deflection yoke. Therefore, the conventional art poses a fundamental problem of failing to adjust the convergence in a partial area on an independent basis even if it is capable of adjusting astigmatism of the comprehensive convergence when adjusting the deflection yoke.
In other words, since adjustment of the convergence of one part results in variation of the convergence of another part, it has been a general practice of performing correction of the misconvergence to create a comprehensively optimal state to date.
The problem is more serious when it comes to a highly defined screen such as an HDTV.
It is, therefore, an object of the present invention to provide a method for controlling digital dynamic convergence and a system thereof for correcting convergence on an individual and independent basis with respect to an each crossing point of a cross hatch pattern on a screen by receiving correction data from outside, storing the received correction data in memories, reading the correction data from the memories in time order of screen scanning by using an image synchronous signal, converting the correction data to a voltage or a current having a structure of outputting to magnetic field adjusting coils.
It is another object of the present invention to provide a method for controlling digital dynamic convergence and a system thereof by generating correction data in accordance with linear interpolation with respect to the areas between crossing points when each crossing point performs correction on a cross hatch pattern screen.
To achieve the above objects according to one aspect of the present invention, there is provided a method for controlling digital dynamic convergence, comprising: a first step of extracting a plurality of screen positions corresponding to the crossing points on the cross hatch pattern screen in a screen display area of a CRT picture device; a second step of mapping a data storing address provided for predetermined data storing means and the plurality of screen positions extracted in the first step; a third step of measuring a degree of convergence astigmatism on each screen position extracted in the first step; a fourth step of generating correction data with respect to the convergence astigmatism at each screen position measured in the third step; a fifth step of storing the misconvergence correction data at each screen position generated in the fourth step in the data storing address mapped in the fourth step; and a sixth step of individually correcting convergence astigmatism at each screen position in the scanning order of electron beams when the image is displayed by reference to the correction data stored in the predetermined data storing means in the fifth step.
Also provided to achieve the objects of the present invention is a digital dynamic convergence control system for individual and independent correction of convergence, comprising: a measuring device for reading a predetermined image pattern displayed on a screen to measure the degree of misconvergence by reference thereto; central control means for generating correction data corresponding to the degree of misconvergence measured by the measuring device; and a digital dynamic convergence correction device for receiving the correction data from the central control means, storing the correction data in an internal memory, reading the correction data from the memory in time of screen scanning by using an image synchronous signal, converting the correction data to a voltage or a current, and outputting the converted voltage or current to magnetic field adjusting coils.
The digital dynamic convergence control device in the digital dynamic convergence control system comprises: a control unit for receiving a control command signal and correction data provided from the central control means, generating a recording address to be stored in the memory according to the control command, and controlling connections of a memory address bus and the data bus either to store the correction data in the memory or to extract correction data from the memory based on the recording address; a memory for storing the misconvergence correction data according to the recording address set by the control unit; an extracted address generation unit for generating extracted addresses to read the correction data stored in the memory by receiving horizontal and vertical synchronous signals extractable from the image signals inputted to a CRT picture device, and synchronizing the horizontal and vertical synchronous signals at scanning times of the crossing points on a cross hatch pattern screen; and an output unit for converting and amplifying the misconvergence correction data outputted from the memory according to the extracted addresses generated by the extracted address generation unit to a voltage or a current so as to be applied to magnetic field adjusting coils having a structure of two poles, four poles or six poles in order for correcting the deflected degree of electron beams.
The control unit of the digital dynamic convergence control system comprises: an address selector for controlling the respective connections of the address bus and the data bus of the memory, the extracted address generation unit and the output unit according to an inputted control signal; and a micro-controller for generating a recording address to be stored in the memory by receiving the control command signal and the correction data provided by the central control means, and manipulating the address selector to transfer the recording address to the address port of the memory when a correction signal has been provided by the control command.
The extracted address generation unit of the digital dynamic convergence control system comprises: a phase-locked loop (PLL) for receiving a horizontal synchronous signal as a reference signal, phase-locking a clock signal required for demultiplication with the horizontal synchronous signal, and outputting the phase-locked signal to synchronize output of the correction data stored in the memory in time of scanning each crossing point when dividing the screen of the cross hatch pattern; a first demultiplier for demultiplying the clock signal outputted from the PLL, and generating a horizontal address signal; a second demultiplier for receiving and re-demultiplying the output signal of the first demultiplier so as to be transferred to the PLL; a third demultiplier for generating a vertical address signal by demultiplying the horizontal synchronous signal as the clock signal by reference to the vertical synchronous signal; and an address generator for generating a memory address to extract the misconvergence correction data stored in the memory by synthesizing the vertical address signal, the horizontal address signal, and the coil address signal.
The third demultiplier of the digital dynamic convergence control system uses the number of horizontal scan lines included in one vertical interval and the number of horizontal scan lines existing on a vertical blanking interval beginning with the vertical synchronous signal to a screen display for setting a predetermined demultiplying number in a vertical direction with respect to the screen division of the cross hatch pattern, and unifying the beginning of the address to the screen starting point when generating the vertical address signal, while the second demultiplier uses the number of horizontal divisions as a control signal of division counting for setting a predetermined demultiplying number in a horizontal direction with respect to the screen division of the cross hatch pattern when generating the horizontal address signal.
The output unit of the digital dynamic convergence control system comprises: a plurality of signal amplifiers matched with each magnetic field adjusting coil corresponding to a horizontal side and a vertical side of the magnetic field adjusting coils having a structure of two poles, four poles or six poles for misconvergence correction; a plurality of D/A converters matched with each of the signal amplifiers for converting an inputted digital misconvergence correction signal to an analog signal; and a plurality of holders matched with each of the D/A converters for receiving the misconvergence correction data outputted from the memory, and renewing the output of the misconvergence correction data with respect to the magnetic field adjusting coils according to the coil address signal generated from the extracted address generation unit.
Each holder of the digital dynamic convergence control system maintains the existing misconvergence correction data until the corresponding coil address signal is provided again and an output renewal is demanded.
According to another aspect of the present invention, the digital dynamic convergence correction device in the digital dynamic convergence correction system comprises: a memory for storing individual misconvergence correction data for each crossing point of the cross hatch pattern screen; an extracted address generation unit for generating extracted addresses to read the correction data stored in the memory by synchronizing the scanning time of the crossing points of the cross hatch pattern screen by receiving the horizontal and vertical synchronous signals extractable from the image signals inputted to the CRT picture device; a control unit for access controlling the individual misconvergence correction data with respect to each crossing point of the cross hatch pattern screen stored in the memory through the extracted address generation unit; and an output unit for converting and amplifying the misconvergence correction data outputted from the memory according to the extracted addresses generated from the extracted address generation unit to a voltage or a current so as to be applied to the magnetic field adjusting coils having a structure of two poles, four poles or six poles for correction of the deflected degree of electron beams.
The control unit of the digital dynamic convergence correction device comprises: an address selector for controlling connections of an address bus of the memory, data bus, the extracted address generation unit and the output unit; and a micro-controller for controlling operation of the address selector and enabling the memory to output the misconvergence correction data stored in the address selected according to the operation of the address selector.
The extracted address generation unit of the digital dynamic convergence correction device comprises: a PLL for receiving a horizontal synchronous signal as a reference signal, phase-locking a clock signal required for division to the horizontal synchronous signal, and outputting the phase-locked signal to generate a coil address signal from the clock signal; a first demultiplier for demultiplying the clock signal outputted from the PLL to generate a horizontal address signal; a second demultiplier for receiving and re-demultiplying the output signal of the first demultiplier so as to be transferred to the PLL; a third demultiplier for generating a vertical address signal by demultiplying the horizontal synchronous signal as the clock signal by reference to the vertical synchronous signal; and an address generator for synthesizing the vertical address signal, the horizontal address signal, and the coil address signal to extract the misconvergence correction data stored in the memory.
The third demultiplier of the digital dynamic convergence correction device uses the number of horizontal scan lines included in one vertical interval and the number of horizontal scan lines existing on a vertical blanking interval beginning with the vertical synchronous signal to a screen display for setting a predetermined demultiplying number in a vertical direction with respect to the screen division of the cross hatch pattern, and unifying the beginning of the address to the screen starting point when generating the vertical address signal, while the second demultiplier uses the number of horizontal demultiplying as a control signal of multiplication counting for setting a predetermined demultiplying number in a horizontal direction with respect to the screen division of the cross hatch pattern when generating the horizontal address signal.
The output unit of the digital dynamic convergence correction device comprises: a plurality of signal amplifiers matched with each magnetic field adjusting coil corresponding to a horizontal side and a vertical side of the magnetic field adjusting coils having a structure of two poles, four poles or six poles for misconvergence correction; a plurality of D/A converters matched with each of the signal amplifiers for converting an inputted digital misconvergence correction signal to an analog signal; and a plurality of holders matched with each of the D/A converters for receiving the misconvergence correction data outputted from the memory, and renewing the output of the misconvergence correction data with respect to the magnetic field adjusting coils according to the coil address signal generated from the extracted address generation unit.
Each holder of the digital dynamic convergence control device maintains the conventional misconvergence correction data until the corresponding coil address signal is provided again and an output renewal is demanded.
According to another aspect of the present invention, the method for controlling digital dynamic convergence comprises: a first step of extracting a plurality of screen positions corresponding to the crossing points on the cross hatch pattern screen in a screen display area of a CRT picture device; a second step of mapping a data storing address provided for predetermined data storing means and the plurality of screen positions extracted in the first step; a third step of measuring a degree of convergence astigmatism on each screen position extracted in the first step; a fourth step of generating correction data with respect to the convergence astigmatism at each screen position measured in the third step; a fifth step of storing the misconvergence correction data at each screen position generated in the fourth step in the data storing address mapped in the fourth step; a sixth step of individually correcting convergence astigmatism at each screen position in the scanning order of electron beams when the image is displayed by reference to the correction data stored in the predetermined data storing means in the fifth step; and a seventh step of performing convergence correction with the lineal interpolating value of the correction data using the interpolation data in a vertical direction in the area between each screen position while performing the correction of convergence astigmatism according to the sixth step.
According to still another aspect of the present invention, the digital dynamic convergence correction system is characterized by performing an individual and independent correction of convergence with respect to crossing patterns of a cross hatch pattern to remove discontinuity of the convergence correction in a vertical direction by means of a linear interpolation in accordance with increase of horizontal scan lines with respect to a screen area between each convergence correction position, the system comprising: a measuring unit for reading a predetermined image pattern displayed on a screen to measure the degree of misconvergence by reference thereto; central control means for generating correction data corresponding to the degree of misconvergence measured by the measuring unit; and a digital dynamic convergence correction unit for receiving the correction data from the central control means, storing the correction data in internal memory, reading the correction data and interpolation data from the memory at screen scanning time by using an image synchronous signal, converting the correction data to a voltage or a current, and outputting the converted voltage or current to magnetic field adjusting coils.
According to another aspect of the present invention, the digital dynamic convergence correction device in the digital dynamic convergence correction system comprises: a control unit either for receiving convergence correction data, interpolation data and a control command signal provided by the central control means, generating a recording address to be stored in memories in accordance with the control command, storing the correction data and the interpolation data in two separate memories based on the recording address, or for controlling connection of a memory address bus and a data bus to extract the correction data and the interpolation data from each memory; a first memory for storing the misconvergence correction data at the crossing point of the cross hatch pattern screen in accordance with the recording address defined by the control unit; a second memory for storing the interpolation data by the control unit to perform interpolation at the crossing point of the cross hatch pattern screen in a vertical direction in accordance with the recording address identical to the first memory; an extracted address generation unit for generating extracted address to read the correction data and the interpolation data stored in the first and the second memories by synchronizing with the scanning time of the crossing points of the cross hatch pattern screen after receiving horizontal and vertical synchronous signals extractable from image signals; an interpolation unit for outputting correction data lineally interpolated in a vertical direction within one vertical interval by computing the correction data and the interpolation data outputted from the first and the second memories in accordance with the extracted addresses generated by the extracted address generation unit based on the horizontal scan line numbers counted from zero in accordance with scanning of a horizontal scanning layer within the one vertical interval with respect to division of the cross hatch pattern screen; and an output unit for converting and amplifying the correction data outputted from the interpolation unit to a voltage or a current so as to be applied to magnetic field adjusting coils having a structure of two poles, four poles or six poles in order for correction of a deflected degree of electron beams.
Also provided to achieve the objects of the present invention is a deflection yoke comprising: a coil separator consisting of a screen unit engaged with a screen surface of the CRT, a rear cover, and a neck unit elongated from a central surface of the rear cover so as to be engaged with an electron gun unit of the CRT; horizontal and vertical deflection coils provided on internal and external surfaces of the coil separator to make magnetic fields deflected in order to deflect electron beams in a horizontal direction and a vertical direction; four pairs of mutually facing magnetic field adjusting coils wound double or triple for correcting information on deflection of the electron beams in accordance with the deflection coils by being operated to have a structure of two or more poles in accordance with an operation control signal; a memory for storing individual misconvergence correction data with respect to each crossing point of a cross hatch pattern screen; an extracted address generation unit for receiving extractable horizontal and vertical synchronous signals from inputted image signals, generating a coil address signal and a horizontal address signal by reference to the horizontal synchronous signal, and generating a vertical address signal by reference to the vertical synchronous signal; and an output unit for converting misconvergence correction data outputted from the memory in accordance with the control signal of the control unit to a current or a voltage so as to be applied to magnetic adjusting coils having two or more poles for correction of the deflected degree of the electron beams.
According to another aspect of the present invention, the deflection yoke comprises: a coil separator consisting of a screen unit engaged with a screen surface of the CRT, a rear cover, and a neck unit elongated from a central surface of the rear cover so as to be engaged with an electron gun unit of the CRT; horizontal and vertical deflection coils provided on internal and external surfaces of the coil separator to make magnetic fields deflected in order to deflect electron beams in a horizontal direction and a vertical direction; four pairs of mutually facing magnetic field adjusting coils wound double or triple for adjusting information on deflection of the electron beams in accordance with the deflection coils by being operated to have a structure of two or more poles in accordance with an operation control signal; a first memory for storing individual misconvergence correction data with respect to each crossing point of a cross hatch pattern screen; a second memory for storing interpolation data for lineal interpolation within a vertical interval in accordance with increase of horizontal scan lines between each crossing point; an extracted address generation unit for receiving extractable horizontal and vertical synchronous signals from inputted image signals, generating a coil address signal and a horizontal address signal by reference to the horizontal synchronous signal, and generating a vertical address signal by reference to the vertical synchronous signal; an interpolation unit for outputting correction data lineally interpolated in a vertical direction within one vertical interval by computing the correction data and the interpolation data outputted from the first and the second memories in accordance with the extracted addresses generated by the extracted address generation unit based on the horizontal scan line numbers counted from zero in accordance with scanning of a horizontal scanning layer within the one vertical interval with respect to division of the cross hatch pattern screen; and an output unit for selectively applying the misconvergence correction data outputted from the interpolation unit based on the control signal of the control unit in accordance with the coil address signal of the extracted address generation unit to the magnetic field adjusting coils having two or more poles for correction of the deflected degree of the electron beams.
Also provided to achieve the objects of the present invention is a display device comprising: a deflection yoke for deflecting electron beams emitted from an electron gun; four pairs of mutually facing magnetic field adjusting coils wound double or triple for adjusting information on deflection of the electron beams caused by an operation of the deflection yoke by being operated in accordance with an operation control signal to have a structure of two or more poles; a memory for storing individual misconvergence correction data with respect to each crossing point of a cross hatch pattern screen; an extracted address generation unit for receiving extractable horizontal and vertical synchronous signals from inputted image signals, generating a coil address signal and a horizontal address signal by reference to the horizontal synchronous signal, and generating a vertical address signal by reference to the vertical synchronous signal; and an output unit for converting and amplifying the misconvergence correction data outputted from the memory according to the extracted addresses generated from the extracted address generation unit to a voltage or a current so as to be applied to the magnetic field adjusting coils having structure of two poles, four poles and six poles for correction of the deflected degree of electron beams.
According to another aspect of the present invention, the display device comprises: a deflection yoke for deflecting electron beams emitted from an electron gun; four pairs of mutually facing magnetic field adjusting coils wound double or triple for adjusting information on deflection of the electron beams caused by an operation of the deflection yoke by being operated in accordance with an operation control signal to have a structure of two or more poles; a first memory for storing individual misconvergence correction data with respect to each crossing point of a cross hatch pattern screen; a second memory for storing the interpolation data by the control unit to perform interpolation at the crossing point of the cross hatch pattern screen in a vertical direction in accordance with the recording address identical to the first memory; an extracted address generation unit for generating extracted addresses to read the correction data and the interpolation data stored in the first and the second memories by synchronizing with the scanning time of the crossing points of the cross hatch pattern screen after receiving horizontal and vertical synchronous signals extractable from image signals; an interpolation unit for outputting correction data lineally interpolated in a vertical direction within one vertical interval by computing the correction data and the interpolation data outputted from the first and the second memories in accordance with the extracted addresses generated by the extracted address generation unit based on the horizontal scan line numbers counted from zero in accordance with scanning of a horizontal scanning layer within the one vertical interval with respect to division of the cross hatch pattern screen; and an output unit for converting and amplifying the correction data outputted from the interpolation unit to a voltage or a current so as to be applied to magnetic field adjusting coils having a structure of two poles, four poles or six poles for correction of a deflected degree of electron beams.